One organic weed killer recipe fills a spray bottle with white, undiluted vinegar and drops of dish soap. Gardeners must spray directly on the weeds and avoid dousing other plants. The weeds should die in 24 hours.
Vinegar contains acetic acid, which is an effective herbicide against weeds and other plants. Vinegars with higher concentrations of acetic acid are more powerful forms of weed killer. Vinegar degrades the cell walls within plants, causing weeds to die quickly. Salt is another organic agent that damages the cellular structure of plants, but the crystals remain in the soil for an extensive period and should only be used on targeted areas.